Rotary piston engine



Jam 10, 1967 H. LAMM 3,297,005

FIG. I

FIG. 2

' H. LAMM ROTARY PISTON ENGINE Jan. 10, 1967 2 Sheets-Sheet. 2

Filed July 17. 1963 INVENTOR. HEINZ LAMM FIG. 5

A TTORNEY 3,297,0l95 RQTARY PilFaTflN ENGHNE Heinz Lannn, Eituttgart-had Cannstatt, Germany, assignor to lhoaimleniiena Airtieugesellschaft, Stuttgart-hinterturirheim, Germany Filed Juiy 17, 1953, Ser. No. 295,632 Claims priority, application Germany, .luly 25, M62,

D 39,452; Dec. ltd, 1962, D 40,591

14 @laims. (@l. 123-8) The present invention relates to a rotary piston internal combustion engine of trochoidal construction in which a polygonal piston provided with piston recesses at the flanks thereof is supported on the eccentric of an eccentric shaft within a housing having side parts and an enclosure body provided with a multi-arched inner surface which has two Zones in proximity to the axis, and in which the piston during the movements thereof relative to the enclosure body and to the eccentric shaft slides with the corners thereof along the inner surfaces and thereby controls gas exchange channels arranged within the area of one of the zones in proximity to the axis, that is within one of the zones more closely approaching the axis of the engine.

With internal combustion engines of this type which are operated as engine with external ignition and in which a spark plug is arranged at the enclosure body within the area of one of the zones approaching the axis, the electrodes of the spark plugs project into a bore which terminates at the inner surface of the enclosure body. It has now been discovered that combustion gases which are within this bore cannot escape in the direction toward the piston recess when the piston is in a position in which it covers with one of the flanks thereof the spark plug bore. The hot gases then blow, when the following radial seal has passed over the spark plug bore, into the next following working chamber. As a result thereof, a local pro-combustion of the fresh gases occurs therein. Additionally, the radial seal is thermally highly loaded. In order to avoid this shortcoming with simple means, the present invention proposes to arrange at each piston flank a groove starting from the piston recess and extending to within the area of the trailing piston corner. By means of such a groove the hot gases located within the spark plug bore may escape during the expansion in the direction toward the piston recess. No significant overflow into the next following working chamber takes place which otherwise would affect disadvantageously the fresh gas side of the engine. The radial seal thereby remains relatively cooler so that the play can be reduced. The possibility of coking and of a jamming is therefore farreachingly reduced by the present invention.

According to a further feature of the present invention, in addition thereto, a groove may be provided at each piston flank which starts from the piston recess and extends to within the area of the leading piston corner. This arrangement has proved itself as particularly advantageous when piston recesses are provided within the piston flanks which are not relatively long but rather compact, because separate spaces result between the piston flank and the inner surfaces of the enclosure body with certain positions of the piston which spaces are separated from the piston recess. Within the leading space as viewed in the direction of rotation of the piston occurs after the ignition the expansion whereas the trailing space continues to compress. The pressure of the gases in these two spaces will be equalized and finds for that purpose exclusively the play between the piston flank and the innor surfaces. Considerable throttling losses result therefrom which are avoided by the two grooves in accordance with the present invention. Additionally, the groove in the direction to the trailing piston corner contributes to the fact that with a sudden pressing-over of the compres- Patent 6 3,297,@5 Patented Jan. in, we?

sion residual volume a more strong eddying or vortexing of the gases within the piston recess takes place. Also with an arrangement of pro-chambers or vortexing Cllfllil' bers in diesel engines, grooves in accordance with the present invention provided in the piston flanks have proved to be advantageous.

Appropriately the grooves may be provided with a continuously decreasing cross section in the direction toward the piston corner.

According to a further development of the present invention, the leading boundary of the piston recess in the direction of rotation is roundedofl in a semi-circularly shaped manner-as seen in plan view on the flank of the piston-and the trailing boundary of the groove extends obliquely to the direction opposite the direction of rotation of the piston.

By such a construction of the piston recess it is possible to produce, in conjunction with the grooves extending to the leading and trailing piston corners within the piston recess, a strong turbulence in the combustion gases by means of which the combustion air is influenced above the piston flank in the sense of a vortexing formation in the interest of a good mixture formation.

According to the present invention, the depth of the grooves starting from the piston recess may correspond to the depth of the piston recess in order to achieve a particularly favorable flow condition.

Accordingly, it is an object of the present invention to provide a rotary-piston internal combustion engine of the type mentioned hereinabove which eliminates, by simple means, the shortcomings and drawbacks encountered with the prior art constructions.

It is another object of the present invention to provide a rotary-piston internal combustion engine in which the combustion gases that may find themselves displaced into the bore receiving the spark plug are able to escape therefrom during operation of the engine, and more particularly in such a manner as to avoid overflowing into the succeeding working chamber.

Still another object of the present invention resides in the provision of a rotary-piston internal combustion engine of the type described hereinabove in which the radial seals are protected against high thermal loads, local precombustion is effectively prevented and no adverse effect needs to be feared on the side of the engine containing the fresh gases.

Additionally, it is another object of the present invention to provide a rotary-piston internal combustion engine which reduces the danger of jamming or coking and in which the pressure of the gases is permitted to equalize without significant throttling losses.

Still another object of the present invention resides in the provision of a rotary-piston internal combustion engine in which means are provided to produce a strong turbulence of the combustion air within the compression space to enhance the mixture formation.

These and other objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, several embodiments in accordance with the present invention, and wherein:

FIGURE 1 is a partial cross-sectional view of a rotarypiston internal combustion engine provided with elongated piston recesses in the piston flanks, the cross section being taken at right angle to the axis of the engine,

FIGURE 2 is a partial plan view, on an enlarged scale, on the piston flank in accordance with the present invention,

FIGURE 3 is a partial transverse cross-sectional view through a rotary-piston internal combustion engine provided with compact piston recesses in the piston flanks thereof,

FIGURE 4 is a plan view, on an enlarged scale, on a modified embodiment of the piston flank in accordance with the present invention,

FIGURE 5 is a partial transverse cross-sectional view through a still further modified embodiment of a rotarypiston internal combustion engine of trochoidal construction with piston recesses in the piston flanks,

FIGURE 6 is a plan view, on an enlarged scale, on the piston flank of the piston of FIGURE 5,

FIGURE 7 is a partial transverse cross-sectional view through the rotary-piston internal-combustion engine taken along line VII-VII of FIGURE 5,

FIGURE 8 is a partial transverse cross-sectional view, similar to FIGURE 3, and illustrating a modified construction of the rotary piston, the outer parts of the internal combustion engine being omitted for sake of clarity, and

FIGURE 9 is a partial transverse cross-sectional view, similar to FIGURE 1, and illustrating a modified construction of the rotary piston, the outer parts of the internal combustion engine being omitted for sake of clarity.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, and more particularly to FIGURE 1 which illustrates a rotary-piston internal combustion engine, reference numeral 1 designates therein the enclosure body provided with the two-arched inner surfaces 2. The triangular piston 3 is rotatingly arranged to rotate in the direction of arrow 4 within the enclosure body 1. The inlet channel 6 and the outlet channel 7 are arranged within the area of the zone 5 approaching the axis of the engine in the enclosure body 1 and the spark plug 9 is arranged within the area of the oppositely disposed zone 8 approaching the axis of the engine. Since the piston 3 slides with the radial seals provided at the piston corners along the surfaces 2, the electrodes of the spark plug 9 do not project beyond the surfaces 2 but are recessed in a more or less large bore 11. An elongated piston recess 13 is provided in each piston flank 12. Inorder that the hot gases disposed within the bore 11 are not closed off by the piston flank 12 when the piston 3 assumes the position indicated in the drawing, a groove 14 is arranged within the piston flanks which directly connects the corresponding trailing flank portion of the piston with the piston recess 13. The gases within bore 11 can thereby expand through the groove 14 in the direction toward the piston recess 13.

As may be seen more clearly from FIGURE 2, the width of the groove 14 may decrease continuously from the piston recess 13 in the direction toward the piston corners. Also the depth of the groove 14 decreases continuously in the direction toward the piston corner, as shown in FIGURE 9.

If the spark plug 9 is not arranged within a center transverse plane of the enclosure body 1 but is disposed offset with respect thereto, then the grooves 14 in the piston flanks 12 also have to be arranged offset.

If the piston 3 is equipped, according to FIGURES 3 and 4, with a compact piston recess 13' in each piston flank 12, it is recommended according to the present invention to arrange in addition to the groove 14 extending toward the trailing piston corner anadditional groove 14' extending toward the leading piston corner. As a result of such an arrangement the closing off of spaces is avoided which occurs when the piston flank approaches in its rotary movements the inner surfaces, so that the gases within these spaces may expand or discharge in the direction toward the piston recess 13 and contribute to a vortex formation within the piston recess.

FIGURE 8 illustrates a rotary-piston internal combustion engine, similar to FIGURE 3 and FIGURE 4 in which, however, grooves 14a and 14a extend from the 4, compact piston recess 13 in the direction toward the trailing or leading piston corners and in which the depth of the grooves 14a and 14a decrease continuously in the direction toward the respective piston corner.

FIGURE 5 illustrates a rotary-piston internal combustion engine in which the triangular piston 103 is rotatably arranged on the eccentric of an eccentric shaft to rotate in the direction of arrow 104 within the enclosure body 101 provided with the two-arched inner surfaces 1112. The inlet channel 106 and the outlet channel 107 are again arranged within the area of the zone 165 approaching the axis in the enclosure body 101 and the spark plug 109 is arranged within the area of the oppositely disposed zone 108 approaching the axis of the engine. The piston 103 slides along the inner surfaces 102 by means of the radial seals 111 provided at the piston corners thereof. A piston recess 113 is provided in each piston flank 112 from which extends a groove 114- into the leading corner of the piston as seen in the direction of rotation thereof and a groove 115 leads in the direction of the trailing corner of the piston. The depth of the grooves 114 and 115 corresponds to the depth of the piston recess 113.

As may be readily seen in particular from FIGURE 6, the forward boundary 116 of the piston recess 113 is rounded-off in a semi-circular shape. The rear boundary 117 of the piston recess 113 extends rearwardly from the groove 115 obliquely to the direction opposite the direction of rotation of the piston.

The flank 112 of the piston 103 produces, depending on the position of the piston to the inlet channel 106, a more or less strong deflection into the working chamber 119 on the part of the combustion air flowing into the working chamber 119 through the inlet channel 106 in the direction of arrow 118. These streamlines are designated in FIGURES 5 through 7 by reference numeral The continuous channel in the center of the flank 112 which is formed by the groove 114, the piston combustion space recess 113 and the groove 115 provides for the combustion air flowing through the inlet channel 136 the possibility to shoot through up to the forward corner or leading corner as viewed in the direction of rotation of the piston. This flow or stream which is designated by reference numeral 121 produces by the high kinetic energy thereof streams or flows 122 within the piston recess 113 which circulate within the piston recess 113 by reason of the rounded-off leading boundary 116 and the oblique backwardly extending rear boundary 117 of the piston recess. A part of the streams 122 is deflected upwardly by the forward boundary 116 of the piston recess in the direction of arrow 123.

Several vortexing centers are produced within the combustion air Without disturbing the filling in the working chamber 119 which vortexing or eddying centers become effective more or less strongly in the individual phases of the combustion and compression stroke. Toward the end of the compression stroke the volume is compressed strongly by way of the groove 121 into the combustion space recess and once again increases the eddying or vor tex which is thus retained up to the point of ignition.

Of course, instead of combustion air, a combustion air gas mixture can also be supplied through the inlet channel without impairing the effect of the particular construction of the piston recess and of the grooves within the piston flank.

While I have shown and described several embodiments in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications within the spirit and scope thereof and I therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

1. A rotary-piston internal combustion engine of trochoidal construction, comprising:

enclosure body means provided with a multi-arched inner surface and with side parts, said multi-arched inner surfaces having zones approaching more closely the axis of the engine,

recessed spark plug means accommodated within bore means provided in said enclosure body means, polygonal piston means provided with piston recesses in the piston flanks thereof,

means including eccentric means for supporting thereon said piston means to provide a sliding movement of the piston corners along said inner surfaces during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means,

gas exchange channel means provided in said enclosure body means Within the area of one of said zones, said gas exchange channel means being valved by the rotary movements of. said piston means,

and groove means arranged in each piston flank below the normal piston flank surface which extends from the corresponding piston recess into the area of the trailing piston corner and terminates near said trailing piston corner, said groove means being substantially in alignment with the aperture of said bore means to permit the escape of gases from said bore means through said groove means.

2. The rotary piston internal combustion engine according to claim 1, wherein the piston recesses extend over the central portions of the respective piston flank.

3. The rotary piston internal combustion engine according to claim 1, wherein each piston flank is provided with a piston recess in the center portion thereof.

4. The rotary piston internal combustion engine according to claim 3, wherein said groove means are disposed exclusively within the trailing portion of the piston flank.

5. A rotary-piston internal combustion engine of trochoidal construction, comprising:

enclosure body means provided with a multi-arched inner surface and with side parts, said multi-arched inner surfaces having zones approaching more closely the axis of the engine,

recessed spark plug means accommodated within bore means provided in said enclosure body means, polygonal piston means provided with piston recesses in the piston flanks thereof,

means including eccentric means for supporting thereon said piston means to provide a sliding movement of the piston corners along said inner surfaces during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means,

gas exchange channel means provided in said enclosure body means Within the area of one of said zones, said gas exchange channel means being valved by the rotary movements of said piston means,

and groove means arranged in each piston flank below the normal piston flank surface which extends from the corresponding piston recess into the area of the trailing piston corner and terminates near said trailing piston corner, said groove means being substantially in alignment with the aperture of said bore means to permit the escape of gases out of said bore means through said groove means,

and further groove means disposed below the normal piston flank surface and extending from the respective piston recess to the leading piston corner.

6. The rotary piston internal combustion engine according to claim 5, wherein each piston recess extends over the central portion of a respective piston flank.

7. A rotary-piston internal combustion engine of trochoidal construction, comprising:

said piston means to provide a sliding movement of the piston corners along said inner surfaces during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means,

gas exchange channel means provided in said enclosure body means within the area of one of said zones, said gas exchange channel means being valved by the rotary movements of said piston means,

and groove means arranged in each piston flank extending from the corresponding piston recess and extending into the area of the trailing piston corner,

and further groove means extending from the respective piston recess to the leading piston corner,

said groove means having a cross section that continuously decreases in the direction toward the respective piston corner.

8. A rotary-piston internal combustion engine of trochoidal construction, comprising:

enclosure body means provided with a multi-arched inner surface and with side parts, said multi-arched inner surfaces having zones approaching more closely the axis of the engine,

polygonal piston means provided with piston recesses in the piston flanks thereof,

means including eccentric means for supporting thereon said piston means to provide a sliding movement of the piston corners along said inner surfaces during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means,

gas-exchange channel means provided in said enclosure body means within the area of one of said zones, said gas exchange channel means being valved by the rotary movements of said piston means,

and groove means arranged in each piston flank starting from the corresponding piston recess and extending into the area of the trailing piston corner and into the area of the leading piston corner,

the leading boundary of the piston recess, as viewed in plan view on the corresponding piston flank, being rounded-off approximately semi-circularly, and the trailing boundary of the piston recess extending obliquely to the direction opposite the direction of rotation.

9. A rotary-piston internal combustion engine of trochoidal construction, comprising:

enclosure body means provided with a multi-arcl1ed inner surface and with side parts, said multi-arched inner surfaces having zones approaching more closely the axis of the engine,

polygonal piston means provided with piston recesses in the piston flanks thereof,

means including eccentric means for supporting thereon said piston means to provide a sliding movement of the piston corners along said inner surfaces during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means,

gas exchange channel means provided in said enclosure body means within the area of one of said zones, said gas exchange channel means being valved by the rotary movements of said piston means,

and groove means arranged in each piston flank starting from the corresponding piston recess and extending into the area of the trailing piston corner and into the area of the leading piston corner,

the leading boundary of the piston recess, as viewed in plan view on the corresponding piston flank, being rounded-off approximately semi-circularly, and the trailing boundary of the piston recess extending obliquely to the direction opposite the direction of rotation,

the depth of the groove means starting from the piston recess corresponding about to the depth of the piston recess.

10. A rotary-piston internal combustion engine of trochoidal construction, comprising:

enclosure body means provided with a multi-arched inner surface and with side parts, said multi-arched inner surfaces having zones approaching more closely the axis of the engine,

polygonal piston means provided with piston recesses in the piston fanks thereof,

means including eccentric means for supporting thereon said piston means to provide a sliding movement of the piston corners along said inner surfaces during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means,

gas exchange channel means provided in said enclosure body means within the area of one of said zones, said gas exchange channel means being valved by the rotary movements of said piston means,

and groove means arranged in each piston flank extending from the corresponding piston recess and extending into the area of the trailing piston corner,

and further groove means extending from the respective piston recess to the leading piston corner,

said groove means having a cross section that continuously decreases in the direction toward the respective piston corner,

the leading boundary of the piston recess, as viewed in plan view on the corresponding piston flank, being rounded-off approximately semi-circularly, and the trailing bounary of the groove means extending obliquely in the direction opposite to the direction of rotation,

and the depth of the groove means extending from the piston recess corresponding to the depth of the piston recess.

11. A rotary-piston internal combustion engine of trochoidal construction, comprising:

enclosure body means provided with a multi-arched inner surface and with side parts, said multi-arched inner surfaces having zones approaching more closely the axis of the engine,

polygonal piston means provided with piston recesses in the piston flanks thereof,

means including eccentric means for supporting thereon said piston means to provide a sliding movement of the piston corners along said inner surface during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means,

gas-exchange channel means provided in said enclosure body means within the area of one of said zones, said gas-exchange channel means being valved by the rotary movements of said piston means,

and groove means arranged in each piston flank starting from the corresponding piston recess and extending into the area of the trailing piston corner and into the area of the leading piston corner,

said groove means having a cross section that continuously decreases in the direction toward the respective piston corner,

the leading boundary of the piston recess, as viewed in plan view on the corresponding piston flank, being rounded-01f approximately semi-circularly, and the trailing boundary of the piston recess extending obli- 8 quely to the direction opposite the direction of rotation. 12. A rotary-piston internal combustion engine of trochoidal construction, comprising:

enclosure body means provided with a multi-arched inner surface and with side parts, said multi-arched inner surfaces having zones approaching more closely the axis of the engine, polygonal piston means provided with piston recesses in the piston flanks thereof, means including eccentric means for supporting thereon said piston means to provide a sliding movement of the piston corners along said inner surface during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means, gas-exchange channel means provided in said enclosure body means within ahe area of one of said zones, said gas-exchange channel means being valved by the rotary movements of said piston means, and groove means arranged in each piston flank starting from the corresponding piston recess and extending into the area of the trailing piston corner and into the area of the leading piston corner, said groove means having a cross section that continuously decreases in the direction toward the respective piston corner, the leading boundary of the piston recess, as viewed in plan view on the corresponding piston flank, being rounded-off approximately semi-circularly, and the trailing boundary of the piston recess extending obliquely to the direction opposite the direction of rotation, the depth of the groove means starting from the piston recess corresponding about to the depth of the piston recess. 13. A rotary-piston internal combustion engine of trochoidal construction, comprising:

enclosure body means provided with a multi-arched inner surface and with side parts, said multi-arched inner surfaces having zones approaching more closely the axis of the engine, polygonal piston means provided with piston recesses in the piston flanks thereof, means including eccentric means for supporting thereon said piston means to provide a sliding movement of the piston corners along said inner surfaces during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means, gas exchange channel means provided in said enclosure body means within the area of one of said zones, said gas exchange channel means being valved by the rotary movements of said piston means, and groove means arranged in each piston flank extending from the corresponding piston recess and extending into the area of the trailing piston corner, said groove means having a cross section that continuously decreases in the direction toward the respective piston corner. 14. A rotary-piston internal combustion engine of trochoidal construction, comprising:

enclosure body means provided with a multi-arched inner surface and with side parts, said multi-arched inner surfaces having zones approaching more closely the axis of the engine, polygonal piston means provided with piston recesses in the piston flanks thereof, means including eccentric means for supporting thereon said piston means to provide a sliding movement of the piston corners along said inner surfaces during the rotary movements of said piston means relative to said enclosure body means and to said eccentric means, gas exchange channel means provided in said enclosure 9 10 body means within the area of one of said zones, piston recess corresponding to the depth of the piston said gas exchange channel means being valved by the recess. rotary movements of said piston means, and groove means arranged in each piston flank ex- References Cited y the Examiner tending from the corresponding piston recess and 5 UNITED STATES PATENTS extending into the area of the trailing piston corner, said groove means having a cross section that cong et a1 tinuously decreases in the direction toward the re- 3213836 10/1965 i 1; spective piston corner. ey Wen at a the leading boundary of the piston recess, as viewed in 10 FOREIGN PATENTS plan view on the corresponding piston flank, being 1,328,707 4/1963 France rounded-off approximately semi-circularly, and the trailing boundary of the groove means extending MARK NEWMAN Primary Examiner obliquely in the direction opposite to the direction of rotation, 15 SAMUEL LEVINE, Exammer.

and the depth of the groove means extending from the F. T. SADLER, Assistant Examiner. 

1. A ROTARY-PISTON INTERNAL COMBUSTION ENGINE OF TROCHOIDAL CONSTRUCTION, COMPRISING: ENCLOSURE BODY MEANS PROVIDED WITH A MULTI-ARCHED INNER SURFACE AND WITH SIDE PARTS, SAID MULTI-ARCHED INNER SURFACES HAVING ZONES APPROACHING MORE CLOSELY THE AXIS OF THE ENGINE, RECESSED SPARK PLUG MEANS ACCOMMODATED WITHIN BORE MEANS PROVIDED IN SAID ENCLOSURE BODY MEANS, POLYGONAL PISTON MEANS PROVIDED WITH PISTON RECESSES IN THE PISTON FLANKS THEREOF, MEANS INCLUDING ECCENTRIC MEANS FOR SUPPORTING THEREON SAID PISTON MEANS TO PROVIDE A SLIDING MOVEMENT OF THE PISTON CORNERS ALONG SAID INNER SURFACES DURING THE ROTARY MOVEMENTS OF SAID PISTON MEANS RELATIVE TO SAID ENCLOSURE BODY MEANS AND TO SAID ECCENTRIC MEANS, GAS EXCHANGE CHANNEL MEANS PROVIDED IN SAID ENCLOSURE BODY MEANS WITHIN THE AREA OF ONE OF SAID ZONES, SAID GAS EXCHANGE CHANNEL MEANS BEING VALVED BY THE PROTARY MOVEMENTS OF SAID PISTON MEANS, AND GROOVE MEANS ARRANGED IN EACH PISTON FLANK BELOW THE NORMAL PISTON FLANK SURFACE WHICH EXTENDS FROM THE CORRESPONDING PISTON RECESS INTO THE AREA OF THE TRAILING PISTON CORNER AND TERMINATES NEAR SAID TRAILING PISTON CORNER, SAID GROOVE MEANS BEING SUBSTANTIALLY IN ALIGNMENT WITH THE APERTURE OF SAID BORE MEANS TO PERMIT THE ESCAPE OF GASES FROM SAID BORE MEANS THROUGH SAID GROOVE MEANS. 